The GridView control raises the RowUpdating event when a row's Update button is clicked, but before the GridView control updates the row. This allows you to provide an event-handling method that performs a custom routine, such as canceling the update operation, whenever this event occurs.

A GridViewUpdateEventArgs object is passed to the event-handling method, which allows you to determine the index of the current row and to indicate that the update operation should be canceled. To cancel the update operation, set the Cancel property of the GridViewUpdateEventArgs object to true. You can also manipulate the Keys, OldValues, and NewValues collections, if necessary, before the values are passed to the data source. A common way to use these collections is to HTML-encode the values supplied by the user before they are stored in the data source. This helps to prevent script injection attacks.